In recent years, semiconductor elements used in a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), and the like are becoming more sophisticated and faster. The amount of heat generation of the semiconductor element thus increases. If the temperature of the semiconductor element rises with increase in the amount of heat generation, this may cause lowering in operation speed, breakdown, and the like of the semiconductor element.
Japanese Laid-Open Patent Publication No. 2009-043978 describes a technique of radiating and cooling the semiconductor element to suppress the rise in temperature of the semiconductor element. FIG. 11 illustrates an example of a semiconductor device of the related art. The semiconductor device has a wiring substrate 70, a semiconductor element 71 mounted on the wiring substrate 70, and a radiator plate 72 formed from a higher thermal conductive metal and thermally coupled to the semiconductor element 71. Further, a heat sink 74 with heat radiation fins 73 is thermally coupled to the radiator plate 72. In this case, the heat emitted from the semiconductor element 71 is once diffused to the radiator plate 72, and then radiated to the atmosphere through the heat sink 74. The heat emitted from the semiconductor element 71 is thus efficiently radiated, and the temperature rise of the semiconductor element 71 is suppressed.
However, since the heat sink 74 is fixed to a mounting substrate 75 such as a motherboard, a region for fixing the heat sink 74 needs to be ensured in the mounting substrate 75. This inhibits miniaturization of the entire device. Furthermore, a fixing tool, such as a screw, or an adhesive needs to be used when fixing the heat sink 74 to the mounting substrate 75. This complicates the manufacturing steps and increases the manufacturing cost. Moreover, if warp occurs in the mounting substrate 75 by heat contraction, or the like, a state in which the radiator plate 72 and the heat sink 74 make point contact or line contact may occur. Therefore, sufficient heat conduction may not be carried out from the radiator plate 72 to the heat sink 74.